U.S. Pat. No. 4,298,025, which is owned by the present assignee, discloses a control valve for use in water softeners having two resin tanks. One of the resin tanks is normally on-line while the other tank is regenerated and placed in a standby condition until the first tank requires regeneration. The disclosed control valve controls which of the tanks is on-line and controls the regeneration sequence of an exhausted tank. The quantity of water treated by a given tank, is monitored by a mechanism that includes a water usage turbine driven by water as it leaves the on-line resin tank. When a predetermined quantity of water is treated, which produces a predetermined number of revolutions in the turbine, a regeneration sequence is initiated which places the standby tank on-line and isolates the exhausted tank. A second turbine, operatively connected to a regeneration sequence control element (in the form of a disk) is rotated by a stream of water that is activated at the beginning of the regeneration cycle. The stream of water physically drives the regeneration control disk (via the turbine and associated drive train) through its sequence. As described above, the frequency of regeneration of the water softener system is determined by the usage turbine which directly measures the quantity of fluid treated by a given tank and transmits that motion up to the use meter disc. The present design is limited to choosing a regeneration start from 1 to 8 times per revolution of the use meter disc located in the top cap region of the control valve.
In U.S. Pat. No. 4,427,549 which is also owned by the present assignee, a deionization method and apparatus is disclosed. The disclosed apparatus includes a control valve similar to the control valve disclosed in U.S. Pat. No. 4,298,025 in that it includes a usage turbine for monitoring the amount of source water treated by a given tank and a regeneration control turbine for driving a control element through a regeneration sequence.
The control valves disclosed in U.S. Pat. Nos. 4,298,025 and 4,427,549 are examples of Non-Electric, Meter Driven, Demand Initiated Regenerating (DIR) fluid treating control valves. These valves by virtue of the design features built into them have enabled them to possess operational benefits unlike similar products currently in the Market. These benefits include: an uninterrupted supply of treated water, counter-current regeneration, high efficiency by metered usage of the water, and regeneration with treated water to name a few.
In the control valve disclosed in U.S. Pat. No. 4,298,025 it should be noted that the motion of the usage turbine is transmitted through a gear train to a rotating eccentric shaft that drives a ratchet pawl, which in turn advances or rotates a circular meter disc. In the device shown in U.S. Pat. No. 4,298,025, the regeneration initiation starts from this circular meter disc. In the existing design, the regeneration start sequence begins when a regeneration start pawl is allowed to contact the lower regeneration control disc by having the cam follower on that regeneration start pawl drop into a cut out under the meter disc. The design allows there to be anywhere from 1 to 8 cutouts equally spaced around the meter disc. Therefore with each revolution of the meter disc a regeneration may be initiated from 1 time per revolution up to 8 times per revolution depending on which meter disc is installed in the device. The choice of this meter disc is made at installation and is based on the water hardness feeding the unit, or other inlet water chemistry measurements, that relate to the volume of that particular water the unit will be able to process effectively. While this allows for some adjustment to properly match the device to a particular inlet water chemistry, it can be seen that some efficiency can be lost when a particular chemistry falls just outside of the gallons offered by, for example a disc having only one slot (one regeneration per rotation) vs. a disc having two slots (two regenerations per rotation). Also the changing of the meter disc requires the unit to be depressurized and the top cap and several pawls to be removed, requiring some level of skill, some time and a potential for possible improper reassembly.